This, however, is not entirely due to the greater exposure of the child to these influences as it grows older, but in part also to the fact that the lining of the air-tubes is less sensitive in early infancy than it afterwards becomes. The young babe if it catches cold gets snuffles, or stoppage of the nostrils, which first become dry, and then pour out an abundant discharge, which sometimes dries and forms crusts, and causes the child to suck with difficulty, and to breathe uncomfortably and with open mouth. In a few days, however, at the worst this discomfort passes away; and the only additional remark I have to make is, that since obstinate snuffles are sometimes a constitutional disease, the doctor's advice should always be sought if they last longer than a week.

It is needless to describe a cold, but it is much more to the purpose to say how its occurrence is to be prevented, and nine times out of ten the observance of two simple rules will suffice for this. First, take care that there is no great difference between the temperature of the day and of the night nursery. The one should never be above 60°, nor the other below 50°, and the undressing and the bath should always take place in the warmer room. Second, never let the child wear the same shoes or boots in the house as it does out of doors. The change should be as much a matter of routine as the taking off its hat or its bonnet.

The domestic management of a cold is simple enough. The usual error is the overdoing precautions, the keeping the room too hot, or overloading the child with extra garments, or its bed with extra covering, by which it is kept in a state of feverishness, or of needlessly profuse perspiration.

If, for the first two days of a bad cold, the child is kept in bed, the room being at a temperature of 60°, with no extra covering on the bed, but a flannel jacket for the child to wear when it sits up in bed to play, a few drops of ipecacuanha wine several times a day, a warm bath, a linseed poultice to the chest, and a little paregoric at night, with a light diet of rice, and arrowroot, and milk, and a roasted apple, and some orange juice; nine times out of ten, or nineteen out of twenty, the cold will pass away with small discomfort to the child and no anxiety to the parents.

Often a child objects to stop all day in its little cot, but move it to its mother's or nurse's big bed; and with a large tray of toys before it, and a little of the tact which love teaches, the day will pass in unclouded content and cheerfulness.

It must of course be borne in mind that measles set in with all the symptoms of a bad cold, followed on the fourth day by the appearance of the eruption; and, moreover, watchfulness must always be alive to detect increase of fever, hurry of breathing, hardness or extreme frequency of cough, the sign of the irritation of the larger air-tubes having extended and become more severe, the evidence that the case from simple catarrh has become one of bronchitis.

Bronchitis and Pneumonia.—It is impossible to enable persons who have not received a medical education to distinguish between a case of bronchitis and one of pneumonia. Neither, indeed, is it of much importance that they should do so, for in both the dangers are of a similar kind, and both call equally for the advice of a skilful doctor.

In bronchitis inflammation affects the lining of the air-tubes, travelling from the larger towards the smaller, and in bad cases extending even to their termination in the minute air-cells. The inflammation leads to the pouring out of a secretion, which by degrees becomes thick like matter, or even very tenacious, almost as tough as though it were a thin layer of skin. If this is very extensive, and reaches to the small air-cells, it is evident that air cannot enter, while that elasticity of the lung which I have already spoken of tends to drive out from the cells the small quantity of air they contained, and the child dies suffocated, partly from the difficulty in the entrance of air, partly from the collapse of air-cells from which the air has been slowly expelled.

In pneumonia or inflammation of the lung-substance the process is different. A portion of one or other lung, sometimes of both, becomes overfilled with blood, or congested, and though the air-tubes themselves are not the special seat of the congestion, yet the air-cells are pressed on by the surrounding swollen substance, and the entrance of air into them is impeded. If the mischief goes further the substance becomes solid and impervious to air, and lastly it becomes softened, its structure destroyed, and infiltrated with matter; the affected part becomes really an abscess, though not bounded by the distinct limits which would shut in an abscess of the hand or the foot. Inflammation, and the formation of an abscess anywhere is, as we know, attended by fever and much general illness, and inflammation of the lung is of course attended by fever and general illness in proportion to the importance of the organ affected. To these, too, must be added all the disturbance inseparable from any ailment which gravely interferes with breathing.

In the great majority of instances inflammation of the lung-substance does not go on to the last stage, and recovery is not only possible, but probable, from congestion and solidification of the organ. Pneumonia, too, usually attacks only a portion of one lung, while in bronchitis the air-tubes of both are always involved. Hence of the two, serious bronchitis is more to be dreaded than serious pneumonia.